// Copyright (c) 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_AURA_WINDOW_TARGETER_H_
#define UI_AURA_WINDOW_TARGETER_H_

#include "base/macros.h"
#include "ui/aura/aura_export.h"
#include "ui/events/event_targeter.h"

namespace ui {
class KeyEvent;
class LocatedEvent;
} // namespace ui

namespace aura {

class Window;

class AURA_EXPORT WindowTargeter : public ui::EventTargeter {
public:
    WindowTargeter();
    ~WindowTargeter() override;

    // Returns true if |window| or one of its descendants can be a target of
    // |event|. This requires that |window| and its descendants are not
    // prohibited from accepting the event, and that the event is within an
    // actionable region of the target's bounds. Note that the location etc. of
    // |event| is in |window|'s parent's coordinate system.
    virtual bool SubtreeShouldBeExploredForEvent(Window* window,
        const ui::LocatedEvent& event);

protected:
    // Same as FindTargetForEvent(), but used for positional events. The location
    // etc. of |event| are in |root|'s coordinate system. When finding the target
    // for the event, the targeter can mutate the |event| (e.g. change the
    // coordinate to be in the returned target's coordinate system) so that it can
    // be dispatched to the target without any further modification.
    virtual Window* FindTargetForLocatedEvent(Window* window,
        ui::LocatedEvent* event);

    // Returns false if neither |window| nor any of its descendants are allowed
    // to accept |event| for reasons unrelated to the event's location or the
    // target's bounds. For example, overrides of this function may consider
    // attributes such as the visibility or enabledness of |window|. Note that
    // the location etc. of |event| is in |window|'s parent's coordinate system.
    virtual bool SubtreeCanAcceptEvent(Window* window,
        const ui::LocatedEvent& event) const;

    // Returns whether the location of the event is in an actionable region of the
    // target. Note that the location etc. of |event| is in the |window|'s
    // parent's coordinate system.
    virtual bool EventLocationInsideBounds(Window* target,
        const ui::LocatedEvent& event) const;

    // ui::EventTargeter:
    ui::EventTarget* FindTargetForEvent(ui::EventTarget* root,
        ui::Event* event) override;
    ui::EventTarget* FindNextBestTarget(ui::EventTarget* previous_target,
        ui::Event* event) override;

private:
    Window* FindTargetForKeyEvent(Window* root_window, const ui::KeyEvent& event);
    Window* FindTargetForNonKeyEvent(Window* root_window, ui::Event* event);
    Window* FindTargetInRootWindow(Window* root_window,
        const ui::LocatedEvent& event);
    Window* FindTargetForLocatedEventRecursively(Window* root_window,
        ui::LocatedEvent* event);

    DISALLOW_COPY_AND_ASSIGN(WindowTargeter);
};

} // namespace aura

#endif // UI_AURA_WINDOW_TARGETER_H_
